Sickle cell disease (SCD) and b-thalassemia together comprise the most commonly inherited diseases in man. The only current therapy for SCD is treatment with hydroxyurea (HU). HU induces fetal hemoglobin (HbF) synthesis in about half of treated patients by as yet unknown mechanism(s), and its long term effects are largely unknown. HbF induction is known clinically to reduce organ morbidity and pain in SCD patients, and to inhibit sickle polymer formation and consequently destruction of erythrocytes in vitro. For the past decade, my lab has studied a fetal g-globin gene repressor called DRED. We recently reported the subunit composition of DRED, which is composed of at least four distinct epigenetic modifier co-repressor multiprotein complexes. One of the modifying enzymes is LSD1, a monoamine oxidase that removes activating chromatin signatures, thereby leading to gene repression. We recently tested a highly specific inhibitor for LSD1 called tranylcypromine (TC). We found that in human CD34+ hematopoietic stem cells induced to differentiate into erythroid cells in vitro, HbF was induced to therapeutic levels in a TC dosage-dependent manner. We have filed a novel use patent for TC, which is already FDA approved and off patent, and intend to test for cryptic properties (HbF induction) in cells and sickle cell mice. Should these preliminary tests be fruitful, we will in the future then initiate clinical trials in ealthy and sickle cell patients.